Question: What rhymes with siliceous mudstone?
Answer: Nothin' good.
"Audacious home phone"
"Hankering ham bone"
"Silly faces headphone"
"Big paces homegrown"
"Scary fairy sunstone"
Recently, whilst murdering time on the NW Rockhounds page, I came across something wonderful. The most beautiful arrangement of words I had seen in weeks! A fellow hound sought identification for their find, and among the praises and well-mannered debate was a combination of words worthy of conceiving a post: "that's some good old siliceous mudstone." What, in the name of every imaginable ice cream flavor in Heaven, was that about? I had to know. In a blaze of thumb action, I dove further into my internet rabbit hole to a trusted rockossary*. Turns out, I am way better at sniffing out stones than the fossil picker of my childhood, but that's a far throw from having any idea what I'm doing.
Prepare for the grandiose unfurling of that which we all seek in our darkest hour: Answers. Specifically, answers to embarrassingly entry-level gemology questions I have harbored since Day 1 with the NW Rockhounds. But, I will get to that in a minute. What this is, right here, under the quivering anticipation of my dashing fingers, is a post about siliceous mudstone [Figure 1]. It is the titillating product of finding myself at a rare intersection where writer's block met braingasmic discovery. Also, this line up of terms relates directly to a neglected list of adventures I have avoided writing up, so really, this is just scholarly self-indulgence (#bloggerlife). Most unlike me, I failed to elicit my usual brand of puntacitidy* for the title. While at a loss for witty word play, I ultimately went with something that rhymes with siliceous mudstone- in not so many words. Now, without further stalling for introductory anecdotes, on to the terms we learns despite the spurns and burns of braving ferns to get to rocks for which we yearns.
There are some words that, when delicately arranged, transform into poetry. 'Siliceous mudstone' is none of these. The term describes that riveting series of volcanic events where silica rich fluid separates from hotshot magma to create the kind of sexy minerals I'm always frothing at the mouth over. The first part of this title's nomenclature, 'silicaceous,' is the adjectivization* of silica, the base for most of the shinies we're all looking for. My understanding is that 'mudstone' is just a fun way of describing sedimentary minerals with high levels of impurity. Many of these materials are collectively known as that antiquitous gemstone, chalcedony [Figure 2].
Although, I should mention that "chalcedony is not scientifically its own mineral species," [Minerals.net/mineral/chalcedony]. Instead, it is a cryptocrystalline form of quartz whose colloquial use overwhelming refers to white or blue chalcedony [Simon & Schuster's Guide to Rocks & Minerals, page 245]. Technically, the term encompasses agate and jasper, along with many other silicates. This hierarchy of quartz was where I kept tripping up in my use of the word 'jasper.'